open access

https://doi.org/10.14943/doctoral.k11612

https://hdl.handle.net/2115/59444

酵母のフォスファチジルセリン非対称分布におけるリン脂質フリッペースの役割に関する研究

英語

2014-12-25

Hokkaido University

65ｐ

In eukaryotic cells, phosphatidylserine is predominantly located in the cytosolic leaflet of the plasma membrane; this asymmetry is generated by an unknown mechanism. In this study, I used the phosphatidylserine-specific probe mRFP-fused C2 domain of lactadherin (mRFP-Lact-C2) to investigate the possible involvement of type 4 P-type ATPases, also called phospholipid flippases, in the generation of this asymmetry in Saccharomyces cerevisiae. Phosphatidylserine was not found in the trans-Golgi Network in wild-type cells, but it became exposed when vesicle formation was compromised in the sec7 mutant, and it was also exposed on secretory vesicles, as reported previously. However, flippase mutations did not reduce the exposure of phosphatidylserine in either case, even at low levels that would only be detectable by quantitative analysis of mRFP-Lact-C2 fluorescence in isolated secretory vesicles. Furthermore, no reduction in the phosphatidylserine level was observed in a mutant with multiple flippase mutations. Because phosphatidylserine was not exposed in a mutant that accumulates endoplasmic reticulum (ER) or cis/medial-Golgi membranes, Golgi maturation seems to be a prerequisite for phosphatidylserine translocation. My results suggest that an unknown mechanism, possibly a protein with flippase-like activity, acts in conjunction with known flippases to regulate phosphatidylserine translocation.

2014-12-25

甲第11612号

博士(生命科学)

(主査) 教授 田中 一馬, 教授 山下 正兼, 准教授 藤田 知道

生命科学院（生命科学専攻）

博士論文

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